Nintendo is fighting against them, but they may be insuring their future through game emulators.

The company filed a patent in the U.S for technology that may let smartphone users play games from three iterations of Nintendo’s Game Boy handhelds on their devices, according to the Wall Street Journal. The technology was called a “software emulator,” and the patent wasn’t only for smartphones, but for modes of public transportation with interactive displays, such as airplanes.

CNET reported that the application for Nintendo’s patent explained that the emulator was software that would allow games made for the Game Boy handhelds to run on other systems. Nintendo had filed a similar patent application back in 2000, updating it in 2003 and 2012, but this application is new.

WSJ also reported that Satoru Iwata, the President of Nintendo, had said before that they would keep their gaming property, such as games like Super Mario Bros., only for their own game systems. The company is facing competition from the growing market of free-to-play games on mobile devices.